Roof-framing square



Dec. 11,1923. A 1,477,002

J. PARKHILL ROOF FRAMING SQUARE Filed Sept. 19. 1921 Patented Dec. ll, 1923.

PATENT OFFICE.

JOHN PRKHILL, OF ROCHESTER, MINNESTA.

noor-rnniirrne SQUARE.

Application area september' 19, 1921. serieu No. 501,782.

TaaZZ inkom t may 00a-cera) Be it known that I, JOHN PARKHILL, a Vcitizen of United States, residing at Roches, ter', in the county o 'fOlmsted and State of Minnesota, have invented certain new and useful Improvements in Roof Framing Squares, of which the following is a specij cation, reference had therein to the ccnpanyine draiiis- The resent invention relates to a square adapteg especially for use by carpenters for use in marking tlie'rafters ofa roof frame, althugh useful for y other similar purposes, and the invention has for object the provision of a novel device of that kind which is simple in use 'and efficient and accurate in the results btained.

Another object is the provision of a square havin suchgradiiations on the arms thereof and gagesslidably mounted on said arms, in erde'rthat the square caribe conveniently used for layingiitand marking oil" different angles, such as when cutting rafters, and the like.

A further object is the provision of such graduationsarranged a n o'vel manner on the square for obtaining the desired results quickly and accurately, and to facilitate the cuttingof the rafters or other boards.

A still furtherobjectis the provision of novel gages mounted on the Varms of the square for cooperation with the 'graduations and to assist in positioning the square on the rafter., or board.

With the foregoing and other, objects in view, which will be apparent as the descrip tion proceeds, the invention resides in the construction 'and arrangement of parts hereinafter described and claimed, it being understood that changes can be made within the scope of what is "claimed without depart-l ing from thespirit oftheinvention.

The invention is illustrated in the accompanying drawing, wherein- Figure `1 is a plan View of the improved square', portions being broken away.

Figs. 2 and 3 are enlarged cross. sections on the respective lines 2l-2and 3- 3 of Fig. 1'.

Fig. 4; isa sectional detail on the line 4-1 ofFig. 3. H, y L. v

Figs. 5, 6and7 are diagrams showing the derivation of scales@ and D.

Fig. 8 is a diagram showing the derivation of scales A and Any suitable square can be used to include the present improvements, and, as shown in the drawing, the square is of the ordinary type, and includes the long arm or blade 10 and the short arm or tongue 11. They outer edges of the arms 10 and 11 Iare graduated from the outer angle of the elbow, as at 12 and 14, respectively, and the inner edges of the arms 10 and 11 are similarly graduated from the inner angle of the elbow, as at 13 and The unit of measurement as herein described is a foot and the fractional graduations are in inches as shown, although the metric or other unit of measurement can be used. The fractional graduations have been eliminated for purpose of simplicity and the use thereof is of course well known.

In carrying out the invention, the arm or blade 10 is provided with the scales A and B thereon, while the arin or tongue 11 is pr0- vided with the scales C and D thereon.

The scale A is obtained from the derivation as depictedin the diagram designated Fig. 8. This Adiagram includes a straight base line HE, from which the perpendicular lines FG and I rise. Any length might be used for the distance between E and F, but in using the foot and inch as a basis of measurement, Vthe line EF is one foot in length, `while the line FG is divided off in .inches from the point F upward. Thus, the graduations on the line FG 'represent the rise in inchesof the roof or inclined surface per running foot horizontally, known in the trade as the rise to the foot of run or simply the rise. Other units of measurement could, however, be used for the several scales of graduations. The distance between4 F and H is equal to the radius of a circle which circuinscribes a square of which a perpendicular extending from the center of the square to either si de, or the radius of the inscribed circle, is equivalent to the length of the line FF. Thus, referring to Fig. 5 in which a square is shown .o'n a smaller 'scale than Fig. 8, the perpendicular KJ is equal to the line EF, and KL is ythe radius of the circumscribing circle. The line HF is equal to the radius KL. The perpendicular I is a distance fromthe point H equal to the distance between the points E and F, or one foot, the line llI being the same as the line EF in length. Lines are drawn from 'the points F1 and I-I to the inch graduations ou the line FG, and the lines distances E1, E2, etc., represent the gradiiati'ons 16 of the scale A.

These graduations .16 start from the 12 inch graduation of the outer graduations 12 of the arm or blade 10, and run aWay from the elbon7 of the square. The outer edge of such arm or blade being used for the graduations of scale A. Thus, the graduations oi such scale A are distances from the outer angle or corner of the elbow of the square, to the respective graduations and are equal to the lines or distances El, E2, etc., of the diagram Fig. 8. The graduations of scale A thus represent the lengths of the hypotenuses of the right/triangles for the vdifferent inches in rise for a ruiming distance horizontally of one toot. The distances between the outer edge of the tongue 11 and graduations of the scale A thus represent the lengths of hypotenuses of right triangles each having as one oi. its sides or the base the unitl or measurement (one foot) and having as their other sides or heights a series of increasing graduated measurements for increasing rises per unit. v

Scale B is also derivedrom Fig. 8, it being noted, as above described, that the line HF is the radius of the circle cireumscribing a square of which the line EF is the radius of the inscribed circle or a perpendicular from the center o' the square to one side, as represented in Fig. 5, while the perpendicular line I is a distance from the point H equal to the line FF. The points of intersection of the line I by the lines extending from the point H to the graduations on the line FG constitute the graduations of the scale B, and such graduations are proportionately smaller or shorter in spacing than the graduations of the scale A, accordingly. The graduations 17 of the scale B, Which are also measured from the outer edge oi"A the arm or tongue 11 of the square, the same as the scale A, represent the distances of the lines from the point H to the line I, Which yare correspondingly shorter than the lines E1, E2, etc., and such graduations 17 also start from the 12 inch graduation ot the scale 12, such 12 inch graduation representing the line I-II and also the line EF. The measurements from the outer edge of the tongue 11 to the graduations of the scale B also represent the lengths ot hypotenuses of right triangles each having as one ol2 its sides or the base the unit oli' measurement and having as their other sides or heights a series of increasing graduated measurements, but these increasing graduated measurements bear the proportions to the increasing rises per the unit of measurement (graduated on the line FG of Fig. 8) as the radius of an inscribed circle ot a square bears to the radius of the circumscribed circle of such square. In other Words, the distances marked olf on the line I in Fig. 8bear the proportion to the distances measured olf en the line FG that the radius (EF or HI) of an inscribed circle of a square bears to the radius (F H) of the circumscribed circle o'l such square.

Scales C and D are derived from a series of regular polygons having tour, five, six and up to any suitable number of sides and angles. Thus, Fig. 5 represents the square, Fig. 6 the pentagon, Fig. 'T the hexagon, etc..` the remaining polygons not being shown. inasmuch as the principle will be understood from Figs. 5. G and 7. In the polygons, the perpendiculars KJ- 'from the centers to the sides or the radii of the inscribed circles are equal, representing one t'ool; in length. whereas the radii of the circumscribing circles are of gradually decreasing lengths from the. square root of 2 to 1 as relnesented by.' the lines KL. The line KL of the square is the longest in length, and the lines KL olf the succeeding polygons having live., six and more sides gradually decrease in length and approach the length of the line or perpendicular KJ (12 inches). The distances lill are marked off on the arm or tongue l1 from the outer edge of the arm or blade l0, rep resented by the graduations 18 of scale C, and such graduations run 'from the end of the arm or tongue 11 toward the angle lint, do not reach the 12 inch graduation of the scale 14. The numbers ol.t the graduations 18 correspond with the number o'l sides (and angles) ot the polygons from which the measurements were obtained.

Scale D is also derived ilrom such polygons and the graduations 19 thereof are measured from the outer edge of the arm or blade 10 also, the same as the gradnatiims 18. The graduations 19 are also numbered according to the number ot sides (and angles) of the polygons 'from which the measurements were obtained. Thus. the graduations of the scale D represent thc half-lengths ot' the sides ot the corresponding polygons JM of Figs. 5, (l. T and so on. The length of distance between .l and M of Fig. 5 is one toot or twelve inches. whiley the lengths JM olE the successive polygons gradually decrease in length and approach zero. Thcgraduations of the scale D thus run from the 12 inch graduation ol`` the scale 1/1 toward the ouler edge ol' the arm or blade 10.

Even it' differently placed, such scales A, B, C and D would be nsenl. bnl the ar rangement. as shown is most desiredile and useful. The use of such scales is latdhtaled by tivo adjustable gages as will he presently described.

A gage 20 is disposed on or across the arin or blade 10 for longitudinal sliding more- Inent thereon, and has the portions 2l and 22 extending at obtuse angles to clear the. outer and inner edges of the blade. respectively, and a flange 28 extends from the portion 21 at an angle to bear against` and a un lll)

lll() tend across the, outerv edge ofthe blade l0, The portions 21 'and 22fpermit the intermediate portion of the gage 20 to bear snugly and flatly on the blade, especially when the gage is tightened on such blade, 'llhe gage or slide 20 has a straight edge 24:, and the corresponding endof` the flange` 23 has a knife edged bearing 25 which, is on a line with thel dependent straight edge which registers With the graduations ofv the scales A and B, whereby such knife edged bearing Will also register With the correspending graduations. Said bearing is also in line with the outer edge of the blade 10.

In order to clamp the gage or slide. 2() to the blade 10 With the flange 23 and knit'e edged bearing 25` thereof tightly against the outer edge of said blade, the port-ion 22 has a flange 26 extending inthe same direction as the flange 23 to projectacross the inner edge ot thev blade, and a resilient ll-clamp 2"? straddles the tlange 2G with oneY portion overlapping said flange and the other portion bearing against the inner edge ofthe blade. as seenl in Fig. 2` A 'screw 28 is threaded through the flange 26 and corlef spending portion of the, clamp 27 and bears against the other` portion of said Clamp` to spring same against the blade, thereby clai'npingthe gage or slide on the blade and pulling the flange 23 tightly against the outer edge of the blade. By loosening the screw 28, the gage can be readilyslid along` the blade to bring the straight edge 24 on the desired graduation of either scale A or B.

The gage or slide ofthetongue ll is indicated at 29 and bears on said tongue. Said gage has a ange 3.0 extending at an angle therefrom to project across and bear against theouter edge of said tongue. Said flange has the ears 3l bent at obtuse angles to extend under the outerredge portions of the tongue, one cornerof onevearl provides a knife edgedbearing 32 on a lino with the straiglitedge 33 ot said gage, said bearing 32 also being on aline with the outer edge ofthe tongue ll. Both, gages thus have straight edges facing or elbow oiC the square, with knife edged bearings on a line with said straight edges and outer edges oli the arms ot the square, to facilitate the positioning ofthe square on the timber. the elbow or angle of the square beingl placed on the timberand the bigmings 25and 32 .against theedge or side` o'l sucli timber. This Will` position the outer edges oi5 the armsin predetermined angles on the timber, accordino' -to thelposi'ions of the gages.

flange 30` and` extends across thebottorn side.. of the tongue ll.V and throughaU-'shaped clamp 35,' ivhich straddlestheinner edgeporthe anglev tion of the tongne, and a nut is. threaded on saidy stem and bears against the clamp 35 Yfor drawing the stem 34e to clamp the flange 30 against the outer edge of the tongue.

rldlie straight edges oft the gages are disposed nearest to. the elbow or verter; ot the square, and the knife edged bearings olithe gages are disposedV at the intersections ot the outer edges ot the arms and straight edges of the gages. ln using tbesquare, the elbow or angle portionthereot is placed on the timber With the knite edged bearings of both gages resting" against the edge or side of the timber, and the marks are mad-e.

along` the outer edges ot the arms.

Directions to4 set the gages at any of the ordinary graduations of the square refer invariablyv to. those graduationsot scales l2 and le along the outer edges oit` the arms.

The majority of'buildings are rectangular (tour sided polygons) but those with six, eight, sixteen7 or more sides are not uncommon. Each number marked, on the scales C and D gives the framing for the polygon which hasthe,corresponding number ot sides. For example, the gage 29 set ata ot either scale C or ,Dgivesthe framing Yfor a four, sided,structure;` at 6 a sixsided structure, etc. y

This root-framing square gives accurate complete and Quick measurements, and is extremely simple. in use,y there being` no calculations to. make, and the directions tor usecan be simple.I ln many cases, it isonly necessary to set` one gage, Thus` to mark common, rafters, all jack ratter side bevels, all hipA side bevels and a number oit other cuts (over 1200 in all) the. gage 29 remains at -l on scale D, Besides all the more commonly used cuts, lengths and bevels, this square gives the more diilicult-such regular hip and, valley. rafters; both purline cuts at hip or val-ley ratter; .hip lengths tov.' any part ot a toot or" run; common ditterence .in lengths ot jaclrrafters 'tor any distance apart; depth ot backing on. hips; dii- `terencebet-Ween the lengths. and cuts of unbacked hip and valley rafters; hood rafters; end cuts on hips to correspond with `soplar@ cuts on `ends oiprojecting common raftersv` etc. The square is also use-Ful in making polygon miter cuts and hopper cuts, and much other ditlicult training..

Form positions of gages to mark common rafters, any pitch, any polygon.` the directions can read el on D, rise on blade. The plumb cut ismarked .by the blade, horizontal cut by tongue., and by marlringthe distance between the bearings consecutively, once for each toot ot run, gives the Whole lengthoit the rafter. lhius, by placing the gage-,29,With the straight edge 33y on the graduationelot scale D, and placing the the., straight vedge.,EZl ont` the loi) graduation of scale 12 representing the rise per foot that is being used, and placing the elbow of the square on the timber with the bearings 25 and 32 contacting with the edge or side of the timber, then the outer edge of the arm or blade 10 can be used for marking the plumb cut, While the outer edge of the tongue or arm l1 is used for marking the horizontal eut. The distance between the bearings 25 and 32 will represent the unit rafter length per running foot, so that by laying off consecutive distances on the timber or rafter by the aid of the bearings 25 and 32, according to the number of running feet, the length of the rafter is readily obtained.

For gage positions to mark side bevels on jack rafters and face bevels on roof boards, any pitch, and polygon, the directions can say number of sides on D, rise on A. The blade l0 then marks the side bevel and the tongue 11 the face bevel. This will take care of eighty or more different pitches on each of eleven different sided (and angled) buildings.

For positions of gages to mark regular hip rafters, any pitch, any polygon, the directions can say number of sides on C, rise on blade. By marking the plumb and horizontal cuts and lengths by the same `method as given for common rafters, gives a large number of cuts and lengths; and by marking the depth of backing by a point along the outer edge of the tongue 11 half the thickness of the rafter from the gage bearing 32, gives many more useful figures.

For miter cuts on polygons, any number of sides, directions can say number of sides on D, l2 on blade, mark by tongue.

For example, to mark a regular hip side bevel on a four sided building, any pitchset the gage 29 on 4 of scale D, and let it remain there for any pitch. Then, for a Y itch of four inches rise set the Oafre 20 P e e at 4 on scale B, and mark by the outer edge of the blade or arm 10. For a rise of six inches set the gage 2O at 6 on scale B, etc. For jack side bevels for the same pitches, use the same figures on the scale A, With the gage 29 still set at t on scale D.

For hundreds of irregular hip rafters, and much other difficult framing, the directions can be equally short and simple, and need v not all be stated here. Some framing can be marked with the aid of only one of the scales, but in other eases it requires a combination of two scales, as in the ease of jack q rafter side bevels, Which require the use of scales A. and D.

Having thus described the invention, what is claimed as new iszl. A square, each arm of Which has a v straight edge and graduations for said edge thereof measured from the corresponding edge of the other arm for a unit of measurement and fractions thereof, one arm having additional graduations for said edge thereof measured from the corresponding edge of the other arm and representing the lengths of hypotenuses of right triangles each having as one of its sides the unit of measurement and having as their other sides a series of increasing graduated measurements for increasing rises per unit.

2. A square, each arm of which has a| straight edge and graduations for said edge thereof measured from the corresponding edge of the other arm for a unit of measurement and fractions thereof, one arm having additional graduations for said edge thereof measured from the correspoiuling edge of the other arm and representing the lengths of' liypotenuses of right triangles each having as one of its sides the unit of measurement and having as their other sides a series of increasing graduated measurements bearing the proportion to the increasing rises per the unit of measurement as the radius of an inscribed circle of a square bears to the radius of the circumscribed circle of such square.

3. A square, each arm of which has a straight edge and graduations for said edge thereof measured from the corresponding edge of the other arm for a unit of measurerment and fractions thereof, one arm having additional graduations for said edge thereof measured from the correspon/,ling edge of the other arm and representing the lengths of the radii of the eircumscribing circles of a series of regular polygons.

4. A square, each arm of which has a. straight edge and graduations for said edge thereof measured from the corresponding edge of the other arm for a unit of measurement and fractions thereof, one arm having additional graduations for said edge thereof measured from the corresponding edge of the other arm. and representing distances proportional to the lengths of the sides of a. series of regular polygons.

5. A square, each arm of which has a straight edge and graduations for said ed ge thereof measured from the corresponding edge of the other arm for a unit of measurement and fractions thereof` one arm having additional graduations for said edge thereof measured from the corresponding edge of the other arm and representing the lengths of hypotenuses of right triangles each having as one of its sides the unit of measurement and having as their other side a series of increasing graduated measurements based on increasing rises per unit, the second named arm having additional graduations for said edge thereof measured from the corresponding edge of the first named arm and representing, in length, differences in proportions of a series of regular polygons.

6. A. square, each arm of which has a straight edge and graduations for said edge thereof measured from the corresponding edge of the other arm for a unit of measurement and fractions thereof, one arm having additional graduations for said edge thereof measured from the corresponding edge of the other arm and representing the lengths of hypotenuses of right triangles each having as one of its sides the unit of measurement and having as their other sides a series of increasing graduated measurements for increasing rises per unit, the first lnamed arm also having graduations for said edge thereof measured from the corresponding edge of the second named arm and representing the lengths of hypotenuses of right triangles having as one of its sides the unit of measurement and having as their other sides a series of increasing graduated measurements bearing the proportion to said increasing rises per unit as the radius of an inscribed circle of a square bears to the radius of the circumscribed circle of such square, the second named arm having additional graduations for said edge thereof measured from the corresponding edge of the first named arm and representing lengths of radii of the circumscribing circles of a series of regular polygons, the second named arm also having graduations for said edge thereof measured from the corresponding edge of the first named arm and representing proportions of the lengths of the sides of such series of regular polygons.

7 A square, one arm of which has a straight edge and graduations for said straight edge, and a gage slidable on said arm and having a straight edge to register With said graduations, said gage having a portion extending across and bearing against said edge of the arm, s aid portion having an ear bent at an obtuse angle so that one corner thereof provides a knife edged bearing at the intersection of said straight edges.

In testimony whereof I hereunto affix my signature.

JOHN PARKHILL. 

